Usagi was a bit selfish and very much a crybaby, and was lazy, clumsy, and an academic underachiever. She was also a terrible cook, as shown several times during the series. She could be jealous and possessive of Mamoru. However, it was shown that she cared very deeply for her friends and family. She was very trusting, and believed that everyone had a better nature; this could be both a character strength and a character flaw at times. She did not believe in killing innocent humans, even when they had been transformed into vicious monsters, and always sought ways to heal them instead. Over the course of the series, Usagi matured a great deal, and even though she was still prone to some childish behavior and bouts of silliness, she became a capable young woman.

Otaku Trivia:

1) When Sailor Moon does the "In the name of the moon" speech, Sailor Moon makes the American Sign Language symbol for "I Love You" with her hands.

2) When Luna checks out the arcade and enter her password is "I love tuna fish and fieldmouse pudding". In the original, the password is "the rabbit of the Moon pounds rice". This password refers to Serena's Japanese name Usagi Tsukino, which means "rabbit of the moon". The Japanese have a legend about a rabbit in the moon that makes mochi (pounded rice) much like the European/American legend of the man in the moon. (episode 1.05 "Computer School Blues").